Geobacter-Methanosaeta DIET Community

A syntrophic two-member consortium consisting of Geobacter metallireducens and Methanosaeta harundinacea that performs direct interspecies electron transfer (DIET) during ethanol oxidation. G. metallireducens oxidizes ethanol and transfers electrons directly to M. harundinacea via electrically conductive pili and aggregates, bypassing the need for diffusible electron carriers like H2 or formate. M. harundinacea uses these electrons to reduce CO2 to methane. This coculture forms conductive aggregates and achieves stoichiometric conversion of ethanol to methane via DIET. Unlike hydrogen-mediated syntrophy, DIET relies on biological electrical connections between cells, with conductive aggregates serving as conduits for long-range electron transfer. M. harundinacea is an obligate acetoclastic methanogen that can also accept electrons via DIET for CO2 reduction, making it unique among acetoclastic methanogens in supporting direct electron transfer mechanisms.